Hydraulically actuated,delayed-opening,door-locking mechanism preferably applicable to household dishwashing and clothes washing machines



Dec. 30. 1969 ZANUSS. 3,486,782

HYDRAULICALLY ACTUATE-D, DELAYED-OPENING, DOOR-LOCKING MECHANISM PREFERABLY APPLICABLE TO HOUSEHOLD DISHWASHING AND CLOTHES WASHING MACHINES Filed sapt. l, 1967 United States Patent 3,486,782 HYDRAULICALLY ACTUATED, DELAYED-OPEN- ING, DOOR-LOCKING MECHANISM PREFER- ABLY APPLICABLE TO HOUSEHOLD DISH- WASHING AND CLOTHES WASHING MACI-HNES Lino Zanussi, Fontanafredda, Italy, assignor to Industrie A. Zanussi S.p.A., Pordenone Udine, Italy, a company of Italy Filed Sept. 1, 1967, Ser. No. 665,000 Claims priority, application Italy, Sept. 3, 1966, Patent 776,634 Int. Cl. Ec 1/02, 21/02; D06f 39/14 US. Cl. 292-177 Claim ABSTRACT OF THE DISCLOSURE Door-locking device for delaying the opening of the door of a dishwasher, washing machine and the like, in which the delayed opening is due to the action of hydraulic pressure.

This invention relates to a door locking mechanism adapted to delay the opening of doors of dishwashers, washing machine and the like, which mechanism prevents the door from being opened during the operation of the machine, thus positively preventing hot water, detergents or sprays from being spilled outwards. The enclosure in which the washing members are housed cannot be reached except when operation and every possible movement have been discontinued.

A main object of the present invention is to provide such a locking device without resorting to electrical circuitry in the neighborhood of, or in contact with, enclosures having a high degree of moisture and which are electrically conductive due to the presence therein of detergent solutions.

This result is achieved with the present delayed-opening door-locking mechanism which essentially comprises a locking member proper which can be shifted in a predetermined direction by utilizing a hydraulic pressure against the action of resilient means to lock the door in its closed position and means for delaying the shifting of said locking member in the opposite direction under the action of said resilient means as said hydraulic pressure is relieved.

The device is illustrated, by way of example only, without any implied limitation whatsoever, in the accompanying drawing, wherein:

FIGURE 1 is a perspective view of a dish-washing machine to which the inventive device has been applied, and

FIGURE 2 is a fragmentary view partly in elevation and partly in cross section of the device.

In the drawings a duct 1 is connected to the circuit of a washing pump 17, and is provided with a flow regulator 2 defined a throttled section or a capillary tube or any other appropriate means. In addition, there is shown a spring-biased body 3 such as a bellows which can be made of rubber, metal or plastic material. The springbiased body 3, whenever necessity or convenience so demand, can be a conventional piston reciprocable within a cylinder. To bottom 3 of the body 3 is afiixed, by appropriate means, a locking stud 4, and a return spring 11 bears at one end against the bottom 3' for maintaining the locking stud 4 in the position shown in solid lines in FIG. 2. The locking stud 4, in its inoperative position, is housed within a supporting member 5 which is integral with a framework 16 and does not project therefrom. The whole assembly is encased in a box 6, which is at- Patented Dec. 30, 1969 fixed to the supporting member 5 by means of suitable fixtures 7. A locking member 8 is affixed to the door 13 so when the door is brought to its closed position by manipulating the handle 15 and causing it to be rotated about the pintles 14 the locking member is in the vicinity of the supporting member 5. The locking member -8 can thus be freely moved in directions shown by the arrows 9 until such time as the locking stud 4 is in the position shown in solid lines in FIG. 2, while it remains engaged when the hydraulic pressure produced by the pump 17 (arrow 10) has extended the body 3 against the action of the return spring 11 and brought the locking stud 4 to position 12 as shown in dotted lines. Thus, the locking stud 4 remains in this position while the pump 17 supplies a positive pressure. As the pressure is released, that is when the operation of the machine is discontinued, the return spring 11, whose force is comparatively weak with respect to the hydraulic pressure, drives out the water through the flow regular 2 during a time which is determined by the flow area of the regulator. Hence, the locking stud 4 will return with a certain time lag to its initial position, and only then will the locking member 8 be able to slide freely, thus permitting the door of the dishwasher, washing machine, etc. to be opened.

All that has been described in the foregoing is also true when the hydraulic pressure used, is the one, for example, exerted by the water head which is necessary for washing, or the pressure of the water feeding main; as properly drawn via a magnetic valve.

The disclosure and the accompanying drawings clearly show the features of the device which actuates, by exploiting a hydraulic pressure, the locking and the delayed opening of the door.

What is claimed is:

1. In a washing appliance of the type having a housing, a moveable door for permitting access to the interior of the housing, a fluid circuit including a pump, a duct leading from the pump and a flow regulator in the duct,

- and a delayed opening locking mechanism for the door,

said locking mechanism including a bellows positioned within the housing and afiixed at one end to the duct in the vicinity of the flow regulator, a stud at the opposite end of the bellows, a locking member on the door, adapted, when the door is closed to be located in the vicinity of the stud, and spring means coacting with the opposite end of the bellows normally urging the stud to the unlocking position, the arrangement being such that upon operation of the pump, the fluid pressure applied to the bellows via the duct overcomes the action of the spring means thus extending the bellows and moving the stud into locking engagement with the locking member whereby the door remains locked during operation of the pump while upon deactivation of the pump, the spring means retracts the bellows driving the fluid through the flow regulator so that the stud returns with a time lag to the unlocking position enabling the door to be opened.

References Cited UNITED STATES PATENTS 2,804,159 8/1957 Gavito 180-82 3,092,576 6/1963 Daubman 210-146 3,196,814 7/1965 Hahn et a1 -18 MARVIN A. CHAMPION, Primary Examiner R. L. WOLFE, Assistant Examiner US. Cl. X.R. 68-196; 134-57 

